SCHENECTADY -- Andrell Leppanen poured gasoline on his stepfather Kevin Hawkins last year at their Bridge Street apartment and lit him on fire, causing his death, the prosecutor in the case told a Schenectady County jury Friday.

Leppanen's attorney, in his own statement to the jury, conceded the same: Leppanen caused Hawkins' death.

How Leppanen arrived at that point, however, will be the central issue in his second-degree murder trial, which began Friday after the seating of a jury.

Did he do it methodically and intentionally to retaliate in the most horrific way for perceived slights against him by Hawkins, as prosecutor Christina Tremante-Pelham argued.

Or, did a long and documented history of mental illness lead Leppanen to that point, as defense attorney Stephen Signore argued.

Tremante-Pelham described to the jury the series of choices Leppanen made, from pouring gasoline into a pot, to throwing it on the sleeping Hawkins and lighting him on fire.

Leppanen even told investigators he chased the fleeing, burning Hawkins to ensure he stayed lit, Tremante-Pelham told the jury.

"It was all part of a series of choices that the defendant made that day," Tremante-Pelham said. "The method that the defendant used, the items he introduced into that room, showed awareness, reflection and planning."

Signore, however, spent much of his opening on Leppanen's mental health history. He grew up with Hawkins as his father. He graduated school and even became a nurse.

Then, in 2013, came his first documented mental health episode. He underwent treatment and took medication. Episodes, however, continued up until days before the attack, Signore said. According to family members, Leppanen suffered from polar disorder and schizophrenia.

"This trial is about Andrell's reality," Signore said.

If convicted of murder, Leppanen could face 25 years to life in state prison. If the defense succeeds in its mental health approach, Leppanen would likely be sent to a secure mental health facility.

The attack happened Aug. 26, 2016, at the 925 Bridge St. apartment where Leppanen lived with his mother and Hawkins.

After he chased the burning Hawkins from the house, Leppanen fled. Hawkins ran to a neighboring house for help, which also happened to be a daycare run by a husband and wife, Tremante-Pelham told the jury.

Hawkins pounded on the door and screamed for help. The wife ushered the children away before her husband opened the door.

"He was screaming and pleading for help," Tremante-Pelham said.

Firefighters, paramedics and police quickly arrived. In the ambulance, Hawkins gave enough information in his agony to lead investigators to identify Leppanen as the suspect, the prosecutor said.

Flown to Westchester Medical Center, Hawkins went into a coma and died two months later.

When investigators caught up with Leppanen, he eventually told them of the animosity he had with Hawkins, Tremante-Pelham said.

He felt demeaned by Hawkins, despised him and believed he was evil, Tremante-Pelham said. "He gives you the reasons why he did it."

Leppanen's mother, Latonia Hawkins, has said Leppanen displayed aggression and indicated problems with both his medication and mood in the weeks leading up to the attack. He twice checked himself in to Ellis Hospital over that time, signing himself out the second time hours after arriving, she said.

The jury will see a video of Leppanen's police interrogation. In it, Leppanen speaks without emotion, without energy, staring off in the distance; he even starts to fall asleep during questions, Signore said. He said they were all symptoms of Leppanen's mental health disorder.

The trial is to continue Monday. Judge Michael V. Coccoma is presiding.